Quartz fibre with hydrogen barrier layer and method for the production thereof

ABSTRACT

A method of manufacturing a quartz glass fibre includes producing a quartz glass primary preform by modified chemical vapor deposition (MCVD) in a quartz glass substrate tube and inserting the quartz glass primary preform into a glass jacketing tube. Defect-generating UV radiation is irridiated into the cross-sectional area of the glass jacketing tube while combining the quartz glass primary preform with the glass jacketing tube in the jacketing process to form a cladding layer to a secondary preform. A quartz glass fibre is pulled from the secondary preform.

Examples of the invention relate to concepts for transmittinghigh-frequency electromagnetic signals and applications related to this,and in particular to a cable and a method for manufacturing the same.

A plurality of options exists for transmitting data. Beginning withsymmetric and asymmetric transmission forms, even hollow waveguides andoptical fibres are customary. Another option is transmission viadielectric waveguides. Dielectric waveguides operate without a share ofa conductive constituent in the transmission medium. On account of theirtransmission principle also they should be arranged dose to the opticalfibres.

When transmitting high-frequency signals, the conductivity of a metal,for example, is used. The energy is carried in this case between twometal conductor surfaces inside a dielectric insulation material. Energytransportation in the hollow waveguide takes place inside a hollowconductive structure coordinated in size to the desired frequency. Highfrequencies coordinated to the geometry of the hollow waveguide arenecessary here to produce a wave mode that is capable of propagation.Symmetric and asymmetric lines up to the lower GHz range can be used forthis (e.g. even up to 25 GHz).

In coaxial structures, the maximum operating frequency range is limitedby what is termed the “cut-off” frequency, above which additional modespropagate. For higher frequencies, the hollow waveguide accordinglyrepresents a more suitable transmission medium.

A disadvantage underlies all the aforesaid transmission principles,however. The energy of the transmission is always carried by means ofmetal conductors. Here the resistance increases at high frequencies dueto the skin effect, leading to a rise in transmission losses. Atfrequencies in the range from a few GHz up to more than 100 GHz thelosses are so great that a sufficiently long distance can no longer bespanned in the application. Moreover, hollow waveguides are inflexibleand have a high weight.

Another means of data transmission is constituted by an optical fibre.In this case, data is sent in a structure consisting of an optical corewith a surrounding “cladding”. The frequencies used here are so highthat they are in the range of light (several hundred terahertz). Onedisadvantage of this transmission form is that an electrical signalalways has to be converted first into a light signal and the materialsinvolved in the transmission must meet high optical demands (e.g.purity, transparency and refractive index).

The technologies presented above are little suited to transmitting datain a frequency range from a few dozen GHz up to a few hundred GHz. Thisis where the dielectric waveguide comes into play. This line consists ofnon-conductive materials. It is important here to provide layering ofdifferent dielectric constants. A very high-frequency signal injectedinto the dielectric waveguide adheres to the boundary layer between highand lower ε_(r)(=relative dielectric constant) and is transmitted in thepropagation direction with little loss.

There are dielectric waveguides in the prior art that are part ofcircuit boards and are is adapted to the conditions predetermined by therespective circuit boards. Here materials are used on the one hand thatdo not meet automotive requirements in relation to flexibility andmechanical installation and cannot be manufactured in any length on theother hand.

Another limitation should be seen in the fact that on account of theirpronounced field pattern outside of the inner region with a large ε_(r),waveguides easily experience crosstalk with adjacent systems. In awaveguide system, for example, two dielectric waveguides, each with ahigh ε_(r) and a circular or at least virtually circular cross sectionare arranged adjacent to one another in a plastic sheath with a lowerε_(r). A high-frequency signal injected into one of these dielectricwaveguides is accompanied by electromagnetic fields, which alsopenetrate the adjacent dielectric waveguide (second waveguide positionedin the vicinity) and produce a signal in this that overlays a usefulsignal injected into this (second) dielectric waveguide and influencesthis.

Cables with dielectric waveguides must where possible be optimised withregard to a reduction in electromagnetic coupling. It is nonethelessdesirable to form cables with a small spatial extension.

A requirement may exist for providing concepts for cables withdielectric waveguides that experience less mutual interference and atthe same time do not take up any more space.

Such a requirement can be met by the subject matter of the claims.

According to a first aspect of the invention, a cable is provided. Thecable has a dielectric medium. The dielectric medium forms a chamber.The chamber can also be filled by the dielectric medium. The cablefurther has a first dielectric waveguide element. The cable also has asecond dielectric waveguide element. The first dielectric waveguideelement is spaced at a distance from the second dielectric waveguideelement. The first dielectric waveguide element runs along alongitudinal direction of the cable through the chamber formed by thedielectric medium. The second dielectric waveguide element runs alongthe longitudinal direction of the cable through the chamber formed bythe dielectric medium. A preferred polarisation direction of the firstdielectric waveguide element differs from a preferred polarisationdirection of the second dielectric waveguide element.

Due to the different preferred polarisation directions, fewerelectromagnetic fields are coupled from the first into the secondwaveguide element and at the same time a space-saving cable is provided.

Each waveguide element can form a waveguide together with the dielectricmedium. The waveguide element can serve here as the transmission medium.

The first and second dielectric waveguide element can run/be arranged inparallel along the chamber or the cable.

The first and second dielectric waveguide element can each be formed totransmit a as high-frequency signal. For example, the first dielectricwaveguide element can be used as a transmitting path and the seconddielectric waveguide element as a receiving path or vice versa. Thefirst and the second dielectric waveguide element can be used in justthe same way as transmitting path or receiving path.

The dielectric medium can surround the first and second dielectricwaveguide elements running in the chamber. The dielectric medium cansurround the first and the second dielectric waveguide elementrespectively here so that at end pieces of the cable, the first andsecond dielectric waveguide element is connectable to a complementaryend piece of a cable or plug. Inside the chamber the dielectric mediumcan fill a section between the first and second waveguide elements.

The preferred polarisation direction of the first dielectric waveguideelement can be predetermined by a cross section of the first dielectricwaveguide element. The preferred polarisation direction of the seconddielectric waveguide element can be predetermined by a cross section ofthe second dielectric waveguide element. The preferred polarisationdirection of the first dielectric waveguide element can differ from thepreferred polarisation direction of the second dielectric waveguideelement by an s angle of at least 45° (or 60° or 75° or 90°), inparticular by an angle of 90°. The cross sections of the first andsecond dielectric waveguide element can be twisted relative to oneanother for this. This means that the first and second dielectricwaveguide element can be e.g. not point-symmetric and/or axisymmetric.For example, the dielectric waveguide elements and the waveguides thusformed are not optical fibres or hollow waveguides.

The cross sections of the first and second dielectric waveguide elementscan be at least substantially identical. By twisting them relative toone another, it can be avoided that waves unintentionally penetrate therespectively other waveguide element and are capable of propagationthere.

The cross section of the first and/or second dielectric waveguideelement can be elliptical or rectangular. The elliptical cross sectioncan have a main axis a and a secondary axis b. The rectangular crosssection can have two side lengths a and b. The main axis a and the sidelength a can be greater than the secondary axis b and the side length b.In particular, the main axis a and the side length a can be 1.25 times(or 1.5 times or 2 times or 3 times or 4 times) greater than thesecondary axis b and the side length b.

The ratio of a to b can predetermine the preferred polarisationdirection of the first and second dielectric waveguide element. If thefirst and second waveguide elements are arranged twisted relative to oneanother in the cable, coupling into the respectively other dielectricwaveguide element can be reduced hereby, as the preferred polarisationdirections of the first and second dielectric waveguide element aredifferent and have a preferred polarisation predetermined by thegeometry, which prevents electromagnetic waves of another polarisationdirection from being able to link in.

A spacing between the first and second dielectric waveguides can besmaller than 4 times (or 3 times or 2 times) a side length a or mainaxis a of the first and/or second dielectric waveguide element.Furthermore, a spacing between the first and second dielectricwaveguides can correspond to at least a side length a or main axis a ofthe first and/or second dielectric waveguide element.

Dielectric constants of the first and second dielectric waveguideelements can be at least substantially identical. The dielectric mediumcan have a different dielectric constant from the first and seconddielectric waveguide element. The dielectric constant of the dielectricmedium can be lower than at least one of the dielectric constants of thefirst and second dielectric waveguide element. The dielectric constantsof the first and/or second dielectric waveguide element can deviate atmost between 0.5% and 5% from one another, for example.

The cable can also have a jacket. The jacket can surround the chamber.The cable can be made more weather-resistant by this. The jacket canlikewise end at the end pieces of the cable.

The jacket can be at least partly conductive. Electromagnetic couplingcan be avoided hereby. In addition or alternatively, the jacket can beat least partly non-conductive. For example, the jacket can be providedwith metal armour.

The jacket can also end flush with the dielectric medium. Water andoxygen inclusions can be avoided hereby, whereby the cable is made moredurable.

The cable can further have a third dielectric waveguide element. Thethird dielectric waveguide element can be spaced at a distance from thefirst and second dielectric waveguide elements. The preferredpolarisation direction of the first dielectric waveguide element cancorrespond to a preferred polarisation direction of the third dielectricwaveguide element. The preferred polarisation directions of the first,second and third dielectric waveguide element can differ respectively byan angle of 60° from one another.

The cable can further have a fourth dielectric waveguide element. Thefourth dielectric waveguide element can be spaced at a distance from thefirst, second and third dielectric waveguide elements. The preferredpolarisation direction of the second dielectric waveguide element cancorrespond to a preferred polarisation direction of the fourthdielectric waveguide element.

Using several waveguides formed by the waveguide elements and thedielectric medium can provide a greater transmission rate and morethroughput. At frequencies of over 100 GHz (without light), a higherbandwidth can likewise be provided.

A respective distance between the first and second waveguide element,and the second and third waveguide element, and the third and fourthwaveguide element as well as the fourth and first waveguide element canbe identical. This distance can correspond to a value A.

A distance between the first and third waveguide element can correspondto a distance between the second and fourth waveguide element. Thisdistance can correspond to a value B.

B can be √2*A. Even if the first and third or the second and fourthwaveguide element have the same preferred polarisation direction,coupling into the respectively other waveguide element can be reduced bythe greater distance (√2 times greater),

The respective distance between the waveguide elements can be determinedstarting out from a centre of a respective cross section of thewaveguide elements in the same cross-sectional plane of the cable.

The chamber can further comprise several segments. In this case, thedielectric medium can likewise be divided into several segments. Eachsegment of the dielectric medium can enclose/surround one of the(first/second/third/fourth) waveguide elements separately (in thechamber). The segments can be mutually in contact. The segments can eachcontact the jacket.

According to a second aspect of the invention, a method is provided formanufacturing a cable according to the first aspect. The methodcomprises provision of a first and second dielectric waveguide element.The first and second dielectric waveguide element are spaced at adistance from one another. The first dielectric waveguide element istwisted compared with the second dielectric waveguide element, so that apreferred polarisation direction of the first dielectric waveguideelement differs from a preferred polarisation direction of the seconddielectric waveguide element in the cable. The method can furthercomprise embedding of the first and second dielectric waveguide elementin a chamber made of a dielectric medium. Alternatively, the embeddingcan comprise embedding of the first and second dielectric waveguideelement in respective segments of the dielectric medium. The chamber canbe formed by stranding of the segments.

Even if some of the aspects described above were described withreference to methods, these aspects can also apply to the cable. In justthe same way, the aspects described above in relation to the cable canapply in a corresponding manner to the method.

It is likewise understood that the terms used here only serve todescribe individual embodiments and are not intended to be considered alimitation. Unless otherwise defined, all technical and scientific termsused here have the meaning that corresponds to the general understandingof the expert in the specialist field relevant for the presentdisclosure; they should be interpreted neither too broadly nor toonarrowly. If specialist terms are used here incorrectly and thus do notgive expression to o the technical idea of the present disclosure, theseshould be replaced by specialist terms that convey a correctunderstanding to the expert. The general terms used here should beinterpreted on the basis of the definition found in the dictionary oraccording to the context; too narrow an interpretation should be avoidedin this case.

It should be understood here that terms such as e.g, “comprise” or“have” etc. signify the presence of the described features, numbers,operations, actions, components, parts or their combinations and do notexclude the presence or the possible addition of one or more otherfeatures, numbers, operations, actions, components, parts or theircombinations.

Although terms such as “first” or “second” etc. are possibly used todescribed various components, these components should not be restrictedto these terms. A component is only to be distinguished from the othersusing the above terms. For example, a first component can be describedas a second component without departing from the protective scope of thepresent disclosure; likewise a second component can be termed a firstcomponent. The term “and/or” comprises both combination of the severalobjects connected to one another and any object of this plurality of thedescribed plurality of objects.

The preferred embodiments of the present disclosure are described belowwith reference to the enclosed drawings; components of the same kind arealways provided here with identical reference characters. In thedescription of the present disclosure, detailed explanations of knownconnected functions or constructions are dispensed with if these deviateunnecessarily from the sense of the present disclosure; such functionsand constructions are comprehensible to the expert, however. Theenclosed drawings of the present disclosure serve to illustrate thepresent disclosure and should not be understood as a limitation. Thetechnical idea of the present disclosure should be interpreted in such away that in addition to the enclosed drawings it comprises also all suchmodifications, changes and variants.

Further objectives, features, advantages and application possibilitiesresult from the following description of exemplary embodiments, whichare not to be understood as restrictive, with reference to theassociated drawings. Here all features described and/or depicted show bythemselves or in any combination the subject matter disclosed here, evenindependently of their grouping in the claims or their references. Thedimensions and proportions of the components shown in the figures arenot necessarily to scale in this case; they may diverge in embodimentsto be implemented from what is shown here.

FIG. 1 shows a schematic representation of a cable with two waveguides;

FIG. 2 shows a schematic representation of a cable with four waveguidesin a first arrangement;

FIG. 3 shows a schematic representation of a cable with four waveguidesin a second arrangement;

FIG. 4 shows a schematic representation of a method for manufacturing acable;

FIG. 5a shows an S-parameter result for a cable with two waveguidesaccording to FIG. 1;

FIG. 5b shows an S-parameter result for a cable with four waveguidesaccording to FIG. 2;

FIG. 5c shows an S-parameter result for a cable with four waveguidesaccording to FIG. 2;

FIG. 5d shows an S-parameter result for a cable with four waveguidesaccording to FIG. 2; and

FIG. 6 shows a schematic representation of a cable with four waveguideelements each enclosed by a separate part of the dielectric medium.

The cable and the method are now described on the basis of exemplaryembodiments.

Specific details are set out below, without being restricted thereto, tosupply a complete understanding of the present disclosure. It is dear toan expert, however, that the present disclosure can be used in otherexemplary embodiments that may deviate from the details set out below.

FIG. 1 shows a schematic representation of a cable 100 with twowaveguides, which are formed by dielectric waveguide elements 110 and120 together with a dielectric medium 150. The dielectric medium 150forms a chamber. The chamber can also be filled by the dielectric medium150. The cable 100 further has a first dielectric waveguide element 110.The cable 100 further has a second dielectric waveguide element 120. Thefirst dielectric waveguide element 110 is spaced at a distance from thesecond dielectric waveguide element 120. The first dielectric waveguideelement 110 runs along a longitudinal direction of the cable through thechamber formed by the dielectric medium. The longitudinal direction runsinto the drawing plane in FIG. 1. The chamber formed can be just a partof the cable 100 here, for example, or extend over the entire length ofthe cable 100. The second dielectric waveguide element 120 also runsalong the longitudinal direction of the cable 120 through the chamberformed by the dielectric medium 150. A preferred polarisation directionof the first dielectric waveguide element 110 differs from a preferredpolarisation direction of the second dielectric waveguide element 120.In FIG. 1, the preferred polarisation directions are in the y-directionin the case of the first dielectric waveguide element 110 and in thex-direction in the case of the second dielectric waveguide element 120.

Due to the different preferred polarisation directions, fewerelectromagnetic fields can be coupled from the first waveguide element110 into the second waveguide element 120 and at the same time aspace-saving cable 100 can be provided.

In the example from FIG. 1, each waveguide element 110, 120 forms awaveguide together with the dielectric medium 150. In this case thewaveguide element 110, 120 can serve as the transmission medium.

The first and the second dielectric waveguide element 110, 120 canrun/be arranged in parallel along the chamber or the cable 100.According to the example from FIG. 1, the first and second dielectricwaveguide elements 110, 120, run in parallel into the drawing plane.They are surrounded here by the dielectric medium 150. Two waveguidesare formed hereby along the cable 100.

The first and the second dielectric waveguide element 110, 120 can eachbe formed to transmit a high-frequency signal. For example, the firstdielectric waveguide element 110 can be used as a transmitting path andthe second dielectric waveguide element 120 can be used as a receivingpath or vice versa. The first and the second dielectric waveguideelement 110, 120 can be used in exactly the same way as transmittingpath or receiving path.

In the example from FIG. 1, the dielectric medium 150 surrounds thefirst and second dielectric waveguide elements 110, 120 running in thechamber. The dielectric medium 150 can surround the first and the seconddielectric waveguide element 110, 120 respectively here so that thefirst and the second dielectric waveguide element 110, 120 isconnectable at end pieces of the cable 100 to a complementary end pieceof a cable 100 or plug. Inside the chamber the dielectric medium 150 canfill a section between the first and second waveguide elements.

The preferred polarisation direction of the first dielectric waveguideelement 110 can be predetermined by a cross section of the firstdielectric waveguide element 1100 The preferred polarisation directionof the second dielectric waveguide element 120 can be predetermined by across section of the second dielectric waveguide element 120. Thepreferred polarisation direction of the first dielectric waveguideelement 110 can differ from the preferred polarisation direction of thesecond dielectric waveguide element 120 by an angle of at least 45° (or60° or 75° or 90°), in particular by 90°. In the example from FIG. 1,the preferred polarisation directions of the first dielectric waveguideelement 110 and the second dielectric waveguide element 120 differ by90°. To this end the cross sections of the first and second dielectricwaveguide elements 110, 120 can be twisted relative to one another. Inthe example from FIG. 1, the cross sections of the first and seconddielectric waveguide element 110, 120 are twisted by 90° relative to oneanother. Due to the twisting relative to one another it can be avoidedthat waves penetrate unintentionally into the respectively otherwaveguide element 110, 120 and are capable of propagation there. Thismeans that the first and second dielectric waveguide element 110, 120can be e.g. not point-symmetric and/or axis-symmetric. For example, thedielectric waveguide elements 110, 120 and the waveguides formed thusare not optical fibres or hollow waveguides.

The cross sections of the first and second dielectric waveguide element110, 120 are identical in FIG. 1 purely as an example.

The cross section of the first and/or second dielectric waveguideelement 110, 120 can be elliptical or, as shown by way of example inFIG. 1, rectangular. The elliptical cross section can have a main axis aand a secondary axis b. The rectangular cross section can have two sidelengths a and b. The main axis a or the side length a can be greaterthan the secondary axis b or the side length b. In particular, the mainaxis a or the side length a can be 1.25 times (or 1.5 times or 2 timesor 3 times or 4 times) greater than the secondary axis b or the sidelength b.

The ratio of a to b can determine the preferred polarisation directionof the first and second dielectric waveguide element 110, 120. If thefirst and second dielectric waveguide elements 110, 120 are arrangedtwisted relative to one another in the cable, as is shown in FIG. 1, theinterference in the respectively other dielectric waveguide element 110,120 can be reduced hereby, as the preferred polarisation directions ofthe first and second dielectric waveguide element 110, 120 are differentand have a preferred polarisation predetermined by the geometry thatprevents electromagnetic waves of another polarisation direction frombeing able to link in.

A distance between the first and second dielectric waveguides 110, 120can be smaller than 4 times (or 3 times or 2 times) a side length a ormain axis a of the first and/or second dielectric waveguide element 110,120. Furthermore, a distance between the first and second dielectricwaveguides 110, 120 can equal at least a side length a or main axis a ofthe first and/or second dielectric waveguide element 110, 120.

The dielectric constants of the first and second dielectric waveguideelement 110, 120 can be substantially identical. The dielectric medium150 can have a different dielectric constant than the first and seconddielectric waveguide element 110, 120. The dielectric constant of thedielectric medium 150 can be lower than at least one of the dielectricconstants of the first and second dielectric waveguide element 110, 120.The dielectric constants of the first and/or second dielectric waveguideelement 110, 120 can deviate at most between 0.5% and 5% from oneanother, for example.

In the example from FIG. 1, the cable 100 further has a jacket 160. Thejacket 160 can surround the chamber. The cable 100 can be made moreweather-resistant hereby. The jacket 160 can likewise end at the endpieces of the cable 100.

The jacket 160 can likewise be conductive. Electromagnetic couplings canbe avoided hereby.

The jacket 160 can also end flush with the dielectric medium 150. Waterand oxygen inclusions can be avoided hereby, whereby the cable 100 isrendered more durable.

The waveguide elements 110, 120 named herein can each consist of amaterial with a high ε_(r). This can be polyethylene (PE), polypropylene(PP), ethylene-tetrafluoroethylene copolymer (ETFE), fluorinatedethylene propylene (FEP), polytetrafluoroethylene (PTFE), polyester(PES), polyethylene terephthalate (PET) or also quartz glass.

The waveguide elements 110, 120 in FIG. 1 each have a rectangular shapeby way of example, but can also have an oval shape. The axis ratio (thusheight to width) here is e.g. at least 1 to 1.4 to 4 (thus maximally 4times wider than high). This axis ratio can determine the preferredpolarisation.

The respective waveguide elements 110, 120 can be surrounded by thedielectric medium 150 with a lower ε_(r). This dielectric medium 150 hasa lower ε_(r) than that of the respective waveguide element 110, 120, inorder to form the waveguide. Foamed materials (thus mixtures of a gasand a plastic) are preferably used for this, PE, PP, ETFE, FEP, PTFE oralso PES can be used here as a polymer. The plastics can be foamed inprocessing. The foaming can take place here due to a chemical orphysical process. The gas bubbles can be smaller than Lambda/4 of awavelength of a useful frequency of the cable 100 in this case. Anotheroption for the dielectric medium 150 is a banding of expanded PTFE. Withthis a significantly lower ε_(r) than that of the respective waveguideelements 110, 120 can likewise be achieved.

The two waveguide elements 110, 120 (also termed wave-carrying elementsor also transmission elements), which are rectangular in FIG. 1, areoriented differently in FIG. 1. For example, the two wave-carryingelements 110, 120 are twisted relative to one another by an angle of90°, as shown by way of example in FIG. 1. This means in detail that thewide side of one element points to the narrow side of the other elementand vice versa. This orientation can avoid mutual interference of thetwo waveguide elements 110, 120 in the cable. Polarised wave types canbe injected into the rectangular (or oval) waveguide elements 110, 120.These are characterised in that they are only capable of propagation inone position, e.g. in the width of one of the waveguide elements 110,120. Although the waves projecting into the dielectric medium 150 alsointersect the other waveguide element 110, 120 twisted by 90° after adistance, they cannot propagate in the length therein, as the height ofthe waveguide element 110, 120, does not match the frequency of thedisruptive coupling

Further details and aspects are mentioned in connection with theexemplary embodiments described below. The exemplary embodiment shown inFIG. 1 can have one or more optional additional features, whichcorrespond to one or more aspects which are mentioned in connection withthe proposed concept or one or more exemplary embodiments describedbelow (e.g. FIGS. 2-6).

FIG. 2 shows a schematic representation of a cable 200 with fourwaveguides, which are formed by a dielectric medium 150 and fourwaveguide elements 110, 120, 130, 140. In addition to the elements andcomponents of the cable 100 from FIG. 1, the cable 200 further has athird dielectric waveguide element 130. According to the example fromFIG. 1, the third dielectric waveguide element 130 is spaced at adistance from the first and second dielectric waveguide elements 110,120. The preferred polarisation direction of the first dielectricwaveguide element 110 corresponds in the example from FIG. 2 to apreferred polarisation direction of the third dielectric waveguideelement 130. In the case of only three waveguide elements 110, 120, 130,the preferred polarisation directions of the first, second and thirddielectric waveguide element 110, 120, 130 can each differ from oneanother by an angle of 60°.

The cable 200 further has a fourth dielectric waveguide element 140. Thefourth dielectric waveguide element 140 is spaced at a distance from thefirst, second and third dielectric waveguide elements 110, 120, 130according to the example from FIG. 2. The preferred polarisationdirection of the second dielectric waveguide element 120 corresponds inthe example from FIG. 2 to a preferred polarisation direction of thefourth dielectric waveguide element 140.

Using several waveguides formed by the waveguide elements 110, 120, 130and 140 and the dielectric medium 150 can provide a greater transmissionrate and more throughput. At frequencies of over 100 GHz (withoutlight), a higher bandwidth can likewise be provided.

A distance between the first and second waveguide element 110, 120, andthe second and third waveguide element 120, 130, and the third andfourth waveguide element 130, 140 and also the fourth and firstwaveguide element 140, 110, is identical hi the example from FIG. 2.This distance is termed value A.

A distance between the first and third waveguide element 110, 130corresponds in the example from FIG. 2 to a distance between the secondand fourth waveguide element 120, 140. This distance can be termed valueB.

B can be √2*A. Even if the first and third waveguide element 110, 130and the second and fourth waveguide element 120, 140 have the samepreferred polarisation direction, a coupling to the respectively otherwaveguide element can be reduced by the greater distance (√2 timesgreater).

The respective distance between the waveguide elements can be determinedstarting out from a centre of a respective cross section of thewaveguide elements in the same cross-sectional plane of the cable 200.

In the case of a cable 200 with four waveguides 110, 120, 130, 140inside the cable 200 (formed by four waveguide elements and a dielectricmedium 150 around the same), the conditions are comparable with the caseof a cable 200 with two waveguides (formed by two waveguide elements anda dielectric medium 150 around the same, see FIG. 1). The directlyadjacent waveguide elements can be rotated by 90° as shown in FIG. 2,diagonally opposed waveguide elements having an identical orientation.Since diagonally opposed waveguide elements have a spacing that isgreater by √2, however, the crosstalk is attenuated even here thereby.

Further details and aspects are mentioned in connection with theexemplary embodiments described above or below. The exemplary embodimentshown in FIG. 2 can have one or more optional additional features, whichcorrespond to one or more aspects, which are mentioned in connectionwith the proposed concept or one or more exemplary embodiments describedabove (e,g. FIG. 1) or below (e.g. FIGS. 3-6).

FIG. 3 shows a schematic representation of a cable 300 with fourwaveguides in a second arrangement similar to FIG. 2, but with anotherorientation of the four waveguide elements 110, 120, 130, 140. Thedielectric medium 150 can have a sufficiently large diameter here toguarantee that the field components of the propagating mode in the lossyjacket material are negligible (if a jacket is used). The jacketstructure to be recognised in the illustration is used here to protectagainst environmental influences (dirt, water and other environmentalinfluences).

Further details and aspects are mentioned in connection with theexemplary embodiments described above or below. The exemplary embodimentshown in FIG. 3 can have one or more optional additional features, whichcorrespond to one or more aspects, which are mentioned in connectionwith the proposed concept or one or more exemplary embodiments describedabove (e.g. FIGS. 1-2) or below (e.g. FIGS. 4-6).

FIG. 4 shows a schematic representation of a method for manufacturing acable. The method comprises provision S410 of a first and seconddielectric waveguide element. The first and second dielectric waveguideelement are spaced at a distance from one another. The first dielectricwaveguide element is twisted by comparison with the second dielectricwaveguide element, so that a preferred polarisation direction of thefirst dielectric waveguide element differs from a preferred polarisationdirection of the second dielectric waveguide element in the cable. Themethod can further comprise embedding S420 of the first and seconddielectric waveguide element in a chamber made of a dielectric medium.

In addition, the method can comprise the separate embedding of the firstand second (as well as third and fourth) dielectric waveguide elementsin segments of the dielectric medium. Furthermore, the method cancomprise stranding of the first and second (as well as third and fourth)dielectric waveguide elements embedded in this way to form a waveguidewith two (four) waveguides. Sheathing can take place as a separate stepto join the stranded elements together to form the cable.

Further details and aspects are mentioned in connection with theexemplary embodiments described above or below. The exemplary embodimentshown in FIG. 4 can have one or more optional additional features, whichcorrespond to one or more aspects, which are mentioned in connectionwith the proposed concept or one or more exemplary embodiments describedabove (e.g. FIGS. 1-3) or below (e.g. FIGS. 5-6).

FIG. 5a shows an S-parameter result for a cable with two waveguides.Curve 5 a 1 describes the insertion loss (IL). Curve 5 a 2 describes thenear end crosstalk (NEXT), Curve 5 a 3 describes the far end crosstalk(FEXT).

FIG. 5b shows an S-parameter result for a cable with four waveguidesaccording to the first arrangement. Here the three FEXT curves 5 b 1, 5b 2 and 5 b 3 are shown in FIG. 5b , which result by measurement duringsupplying of one of the waveguide elements.

FIG. 5c shows an S-parameter result for a cable with four waveguidesaccording to the first arrangement Here the three NEXT curves 5 c 1, 5 c2 and 5 c 3 are shown in FIG. 5c , which result by measurement duringsupplying of one of the waveguide elements.

FIG. 5d shows an S-parameter result for a cable with four waveguidesaccording to FIG. 2. The insertion loss is provided in FIG. 5d by 5 d 1.The FEXT curve 5 b 1 further corresponds to the FEXT curve 5 d 3. TheNEXT curve 5 c 1 also corresponds to the NEXT curve 5 d 2.

FIG. 6 shows a schematic representation of a cable 600 with fourwaveguides 110, 120, 130, 140 each surrounded by a separate part of adielectric medium 150. The chamber in the example from FIG. 6 comprisesseveral segments of the dielectric medium 150, as described above. Inthis case the dielectric medium 150 is divided into several segments.Each segment of the dielectric medium 150 encloses/surrounds one of the(first/second/third/fourth) waveguide elements 110, 120, 130, 140separately (in the chamber) in the example from FIG. 6. The segments canbe in mutual contact. The segments can each likewise contact the jacket160.

If great mechanical loads act on the cable 600, it can be advantageousto strand the waveguides (formed by a respective segment of thedielectric medium and a corresponding waveguide element 110, 120, 130,140). Here each waveguide element 110, 120, 130, 140 can be fabricatedtogether with the dielectric medium 150 as a separate (individual)waveguide of the cable 600. Several individual waveguides of the cable500 can then be stranded with one another. Stranding with reverse twistcan be used in this case. It is thereby guaranteed that the orientationsof the waveguides and also of the corresponding waveguide elements 110,120, 130, 140 are not displaced to one another.

Moreover, a torsion of the transmission elements 110, 120, 130, 140negatively affecting the transmission properties can be avoided. It isnot absolutely necessary here, however, that the dielectric medium 150has a round outer contour. A roughly rectangular contour has advantagesin the assignment to one another here. This is because round surfaceseasily twist in relation to one another, while faces brace one another.A continuation consists in a segmented outer form of the individualcomponents.

Further details and aspects are mentioned in connection with theexemplary embodiments described above. The exemplary embodiment shown inFIG. 6 can have one or more option& additional features, whichcorrespond to one or more aspects, which are mentioned in connectionwith the proposed concept or one or more exemplary embodiments describedabove (e.g. FIGS. 1-5).

According to one or more of the aforesaid aspects, a cable optimised forcrosstalk can be provided with two or four waveguides in a commonjacket. The waveguide elements contained in the cable can each have arectangular or oval cross section (height to width ratio between 1:1.4to 4). The dielectric medium 150 used in the cable can be one part(common element for all waveguide elements) or a plurality of parts.Each part can then surround a respective waveguide element separately.The parts surrounding the corresponding waveguide elements can then bestranded with one another, e.g, with reverse twist during production, toretain the orientation. These individual parts can have a rectangular orsegmented cross section.

The cable described above can have the following advantages. Adielectric waveguide can be very light and flexible. It does not break,for example, even in the event of maximum reverse bending demands. Inaddition, a transmission frequency can be extremely high, e.g. in therange of 100 GHz to 150 GHz, or also over 50 GHz, over 70 GHz, over 90GHz, over 100 GHz, over 120 GHz, over 130 GHz or over 140 GHz. Anextremely large data bandwidth can be provided thereby. Moreover, it canbe made possible with the structure described to double or quadruple thetransmissible bandwidth with respect to a structure with only one.transmission element without channels significantly influencing oneanother.

Furthermore, cables of this kind have the advantage of being able tocarry no current. Since no conductor is present, therefore, there cannotbe any sparks either. A damage risk can be reduced and electromagneticcompatibility improved by this.

The aspects and features that were mentioned and described together withone or more of the examples and figures described in detail above canfurther be combined with one or more of the other examples to replace asimilar feature of the other example or to introduce the featureadditionally into the other example.

The present disclosure is not limited in any way to the embodimentsdescribed previously. On the contrary, many opportunities formodifications thereto are evident to an average expert without departingfrom the fundamental idea of the present disclosure as defined in theenclosed claims.

1. A method of manufacturing a quartz glass fibre, said methodcomprising the steps of: a) producing a quartz glass primary preform bymodified chemical vapor deposition (MCVD) in a quartz glass substratetube; b) inserting the quartz glass primary preform into a glassjacketing tube, c) irradiating defect-generating UV radiation into thecross-sectional area of the glass jacketing tube while combining thequartz glass primary preform with the glass jacketing tube in thejacketing process to form a cladding layer on the fibre core to asecondary preform; and d) pulling a quartz glass fibre from thesecondary preform.
 2. The method of claim 1, wherein thedefect-generating UV radiation generates E′ and NBOHC defects in thecladding layer of the quartz fibre.
 3. The method of claim 1, whereinthe defect-generating UV radiation is irradiated into the glassjacketing tube.
 4. The method of claim 1, wherein the glass jacketingtube consists of quartz glass having an OH concentration of ≤0.2 ppm, achlorine content of 800-2000 ppm, and/or a refractive index of +0.35 to+0.5×10⁻³.
 5. The method of claim 1, wherein the quartz glass primarypreform has a fluorine-doped radial layer on the fibre core.
 6. Quartzglass fibre produced or producible by the method of claim
 1. 7. Quartzglass fibre, comprising: a) a fibre core of quartz glass, b) afluorine-doped radial layer on the fibre core, c) a cladding layer ofquartz glass, wherein d1) the cladding layer has E′ and NBOHC defects,or, d2) the cladding layer has Si—OH and Si—H compounds.
 8. The quartzglass fibre of claim 7, wherein the cladding layer is quartz glasshaving an OH concentration of ≤3.2 ppm, a chlorine content 800-2000 ppm,and/or a refractive index of +0.35 to +0.5×10⁻³ on the fibre core, andwherein the cladding layer preferably has a higher density of E′ andNBOHC defects than the fibre core.
 9. The quartz glass fibre of claim 7,wherein the quartz glass fibre has no further doped layers.
 10. Thequartz glass fibre of claim 7, wherein the quartz glass fibre has nohermetic coating.